1. Field of the Invention
The present invention relates to a power converter module, to a photovoltaic system having a power converter module, and to a method for operating a photovoltaic system.
2. Description of Related Art
Photovoltaic systems, or other systems having DC sources, such as fuel cells, galvanic cells, or DC generators, generally make use of power converters that convert the direct voltage provided by the DC source, for example a photovoltaic module having one or more solar cells, into the required DC layers and/or AC layers.
Standardly, a photovoltaic module, or a plurality of photovoltaic modules, is coupled to an intermediate circuit via an input DC converter, for example a flyback converter. From the intermediate circuit, power can then be fed into a battery storage device via a further DC converter. In addition, an inverter, galvanically separated if warranted, can be coupled to the intermediate circuit, and can take power from the intermediate circuit for feeding into an AC network.
In addition, it is known to operate the input DC converter at the operating point of maximum power drain from the photovoltaic module, by implementing a maximum power point regulation (maximum power point tracking, MPPT) in an MPP control unit. Here, the MPP control unit controls semiconductor components in the input DC converter in such a way that the power taken from the photovoltaic module is a maximum amount, because the optimal operating point of the photovoltaic module can fluctuate, for example due to varying solar radiation, or the occlusion of individual solar cells.
German utility model publication DE 21 2008 000 035 U1 discloses an inverter having a power-regulated DC converter at the input side, a DC converter at the output side, and an inverter at the output side. US Patent Application Publication No. 2004/0125618 A1 discloses a modular inverter system having a multiplicity of DC converters that feed an intermediate circuit, as well as an inverter fed from the intermediate circuit.
There is a need for solutions for power converters fed from DC sources, in which the topology of the power converter can be simplified, the efficiency increased, and the power loss minimized.